Could we fly a bizjet into a remote strip in the Himalayas?

Managing a fractional ownership business like NetJets has been compared to maintaining an antique watch: Every cog, spring, and wheel must mesh perfectly. My particular cog is flight operations engineering, a field dedicated to solving the daily problems that most air travelers never consider: Our pilots can’t just gas up and take off. For each flight, we must answer fundamental questions. How much can we carry? Where’s the worst place to lose an engine? What happens next? Our job is to simplify the answers so pilots and dispatchers don’t have to dig too far into the flight manuals, pound away on calculators, or call the ops engineer at 3 a.m. The tables and charts they rely on for those can-we-do-it questions are the result of hours of research and calculations. Still, one 2008 trip required the most extensive research effort I’ve ever been part of.

Tucked away deep in a valley in the Himalayan country of Bhutan is the remote town of Paro. Of course, “remote” depends on one’s perspective: Considering that Paro hosts its country’s lone commercial airport, the place is a bustling metropolis. One of our charter clients, a television travel program, had requested a flight to Paro as the highlight of an already complex trip two months away.

In the on-demand charter business, two months is a luxury. And judging by our chief pilot’s reaction, this trip looked to be particularly exotic. Studying maps of the airport environment, we found it sat at 7,000 feet above sea level and was surrounded by mountains topping 18,000 feet. Adding to the challenge, Paro is a daytime-only airport that offers only Visual Flight Rules approaches, landings for aircraft in our category, and takeoffs. The crew would be flying into a granite bowl without a usable instrument approach, and we had no time to create customized procedures. The answer seemed to be: “No way we can do this.”

But then the pictures showed up. After doing his own research, our customer had found a story in Boeing’s Aero magazine about proving flights the company had made into Paro with a Boeing Business Jet, an executive-class 737-700—the very aircraft we’d be flying. Once we were faced with photographic evidence of an identical airplane at the same airport, “No way” became “Now what?”

Fortunately, we were able to contact the performance engineer who’d designed Boeing’s procedures, and the test pilot who made the flights. Both had their own perspectives and tales: While looking for Paro, it was reputedly easy to become disoriented and turn down the wrong valley. There had been reports of pilots flying to the edge of a stall to escape that very situation.

We were able to get remarkably detailed topographic maps created by the former Soviet Union and terrain data from NASA’s space shuttle radar topography mission. Charts, performance tables, and pencil in hand, my first crack at a departure plan would maximize the crew’s time climbing straight up the valley, but in the end bore a remarkable resemblance to a treble clef superimposed on a topographic chart.

“That’s it,” I replied. “You guys wanted to leave Paro with a nice, steady climb up out of the valley. That’s the only way I can find to do it.”

Which was true, but the departure we had jokingly named the Whifferdill had a critical weakness: The crew could indeed make a gentle climb straight up the valley and keep any turns within 15 degrees of bank angle, but that would eventually lead them into a blind turn around a mountain ridge—still below the peaks, with God-knows-what kind of weather in the next valley. There was plenty of maneuvering room, but they couldn’t risk flying into unseen weather around the bend with mountains still towering above them and no instrument references.